This invention relates generally to the field of implantable medical devices, and more particularly to implantable heart monitors and therapy delivery devices.
A wide variety of implantable heart monitors and therapy delivery devices have been developed including pacemakers, cardioverter/defibrillators, heart pumps, cardiomyostimulators, ischemia treatment devices, and drug delivery devices. Most of these cardiac systems include electrodes for sensing and sense amplifiers for recording and/or deriving sense event signals. Often the sense event signals are utilized to control the delivery of pacing stimuli in accordance with a predefined algorithm.
Several prior art disclosures have been made suggesting methods seeking to optimize pacing stimuli to a patient""s heart including:
All patents listed in Table 1 above are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description and Claims set forth below, many of the devices and methods disclosed in the patents of Table 1 may be modified advantageously by using the teachings of the present invention.
In general, the invention provides an implantable medical device system designed to optimize blood flow through the coronary artery of a patient""s heart by monitoring blood exiting through the coronary sinus. The invention provides solutions to problems existing in the prior art by providing closed loop regulation of pacing stimuli in response to sensed blood velocity through the coronary sinus so as to maximize oxygen supply to the cardiac muscle.
According to one feature, an implantable medical device system includes a left ventricular pacing lead for implantation in the great cardiac vein via the coronary sinus of a patient""s heart. The pacing lead includes a flow sensor for measuring the velocity of blood flowing through the coronary sinus. An implantable medical device (IMD) coupled to the pacing lead monitors a blood flow signal from the sensor and delivers pacing pulses to the patient""s heart as a function of the blood flow signal. The IMD calculates the integral of the blood flow signal to estimate blood flow volume and adjusts a pacing parameter of pacing pulses delivered to the heart in order to maximize the blood flow.
The features of the invention may be incorporated in a variety of embodiments. For example, in one configuration, the IMD continuously adjusts the atrial and ventricular (AV) delay in order to maximize the integral of the velocity signal received from pacing lead. In a multisite pacing system, where the IMD includes a plurality of ventricular pacing leads for pacing the left and right ventricles, the IMD can also adjusts the interventricular delay.